Time to start playing with the supercharged Z again.Thought I would ask all you high horsepower guy's this question.

I have Hooker longtubes into a 4" mufflex with spintech muffler right now.
The mufflex always fit like crap and is heavy. My question is should I bolt a 4" Borla XR1 onto the end of the Y-pipe with a turn down or should I put 2 3" Xr1's on the end of each header with turn downs? Which would make more power? I will not be running pipes over the axle just dumping it underneath before the rear axle.

Thanks
John